Airplane



Oct. 7, 1930. R. H. UPSON 1,777,593

AIRPLANE Filed June 16, 1928 2 Shuts-Sheet 1 INVENTOR E/MPH h! UPJO/VATTORNEY R. H. UPSON Oct. 7, 1930.

AIRPLANE Filed June l6, 1928 2 Sheets-Sheet 2 IA'VENTOR B y HALF/7 H.UPCSOM A TTORNEV Patented Oct. 7, 1930 UNITED STATES RALPH H. UPSON, OFGBOSSE ILE, MICHIGAN AIRPLANE Application filed June 16,

Thisinvention relates to airplanes and particularly to those in whichcertain sections thereof are provided with a metal or like stresstransmitting skin or covering, the

principal object being the provision of means for maintaining such skinor covering in its normal position and preventing undesirable deflectionof the same.

Another object is to provide means for maintaining the interior of anairfoil section under a pressure commensurate with the maximum pressureat any time present on the exterior of such section.

Another object is to provide an airfoil section, the interior of whichis divided into a plurality of separated compartments, and a providingmeans for maintaining each compartment with an internal pressuresubstantially equal to the maximum exterior pres;

0 sure which at any time may be acting upon the same.-

Another object is to providea new and novel wing slot for airplanewings.

Another object is to provide a new and novel form of wing slot forairplane wings which at the same time will maintain an internal pressureon the wing.

Another object is to provide anovel type of wing slot for airplane wingswhich Wlll be operative only during those intervals when such slots arebeneficial.

Another object is to provide a wing slot for airplane wings withautomatically actuated means for closing and opening the same to thepassage of air to obtain optimum operating conditions.

' A further object is to provide an airfoil section with means formaintaining the interior thereof under pressure, automatically k -Wactuated valve mechanisms being provided to accomplish the same. I y Theabove being among the objects of the present invention, the sameconsists in cer-' tain features of construction and combinations ofparts to be hereinafter described with reference .to the accompanyingdrawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates suitable embodiments ofthe present 1928. Serial No. 285,921.

invention, and in which like numerals refer to like parts throughout theseveral different v1ews,-

Fig. 1 is a more or less diagrammatic side elevation of the airplane.

Fig. 2 is a plan View of one of the wings of the airplane shown in Fig.1.

Fig. 3 is a sectional view taken on the line 33 of Fig. 2.

Fig. A is a sectional view taken on the line 4-4 of Fig.2.

Figs. 5 and 6 are sectional views showing two positions of amodification of the constructionshown in Fig. 4.

Fig. 7 is a partially broken side elevation ofarudder. I d

Fig. 8 is a sectional view taken on the line 8-8 of Fig. 7.

In air lane construction it is desirable because 0 the deterioration towhich fabric covering is subjected due to the elements, to employ ametal covering. The chief disadvantage of metal coveringlat the presenttime is the increase in weight t ereofoverthe conventional fabriccovering. This has been minimized to some extent in some constructionsby utilizing the metal covering'as a stress transmittm member. The usualmode of accompli ing this is to corru ate" or rib the covering arallelwith the directlon of movement, t us imparting strength 1 to the winginthat direction which permits the use of a lesser number-of ribs, butsuch corrugated or ribbed construction of the covering does not aid inincreasing the strength of the wing along the length thereof or at an. apreciable angle to the corrugations or'ribs.

e useof the metal covering as a stress transmitting member may begreatly increased, and thereby allow' a decrease in the ultimate weightof a metal covered wing, by the employment of unribbed or uncorrugatedmetal covering so that such covering may transmit stresses in alldirections, thereby permitting the internal bracings and load carryingmembers to be materially reduced in size and weight over those necessaryin fabric and corrugated metal covered constructions.

However, heretoforegthere have been certain disadvantages apparent intheempl0y- 1 ment of a plain metal covering caused'primarily by the factthat such covering is eas- 11y flexed between its lines or points ofsupport so that under a change of air pressure V on the wing. from apositive pressure to a ber- 16 and a supplementary spar 17. Ex-- tendingbetween and secured to the members 15, 16 and 17 are a plurality ofspaced rib members 18. A plain metal skin or, covering 19 is providedover and secured to the ribs 18 and members 15, 16 and 17, the coveringextending to the rear end of the ribs 18 where it may be connectedtogether as at 20. The spar 15 may be made imperforate, as shown, as mayalso the supplementary spar 17, thus forming the interior of the winginto three spaced chambers 21, 22 and 23, each substantially air tightand sealed from each other. In accordance with the present invention Iform an opening 24 in the nose of the wing at or near the point wherethe maximum positive air pressure is normally exerted thereon, and formopenings 25 and 26 in the lower walls of the chambers 22 and 23respectively at the points thereon where the maximum.-

positive air pressure is exerted on such walls. The result is thatduring flight of an airplane provided with the chambers apertured, asindicated, the interior of each chamber is subjected to the maximumpressure which acts on the exterior of its surfaces and thus insures themetal covering against being depressed at anytime due to a pressureacting on the exterior thereof. I find that this effectively revents anyinjurious snapping action of t e covering whatsoever.

The openings 24, 25 and 26 may, 'as'will readily be apparent, be formedas a plurality of separate and independent openings, orv each maycomprise a slot extending contin-.

uously from one end of the wing to the other, or for any portion of thelength thereof. It will also be apparent that the interior of the wingmay bedivided into any number of chambers that may be found desirable,and each of the chambers provided with its own opening or openings, andin some cases, it may be found desirable to form the interior of thewing into one single chamber, or in a plurality of chambers extendingtransversely of the length of the wing. One or more of such chambers mayalso or alternatively take air from a duct such as 77 in Fig. 1 whichconnects with a proper source of pressure,

Where the present invention is. applied to the rudders or elevators inwhich the surfaces thereof may be alternately subjected to either apositive or negative pressure, the application of the maximum pressureacting on the exterior thereof to the interior thereof may be taken careof as indicatedin Figs. 7 and '8. As indicated in those figures, arudder indicated generally as 28 is shown, which is pivot-- allysupported on a post 29 suitably supported as at 30.. The interiorstructure of the rudder may comprise a plurality of apertured ribs suchas 31 and apertured cross members 32. The ribs 31 and members 32 arecovered by a plain metal sheeting 33. Inaccordance with the presentinvention I form one or more openings 34 in the covering 33 on each sideof the rudder at a. point thereon at or adjacent to the point at whichthe maximum exterior pressure may act upon it, and I preferably providea scoop such as 35 for directing the air into each of the openings 34.It will be recognized that when the rudder is turned to turn theairplane, one side surface-thereof will be subjected to a negativepressure, and in order to prevent the air entering the opening.oropenings 34 on one side of the rudder during such a time from escapingthrough the opening 34 on the opposite side of the rudfler, I provide onthe interior of the rudder a fabric or like flap 36 secured at one edgeadj acent the corresponding opening 34 and positioned so as to overlapthe same. These flaps 36-permit ready entrance of air into the interiorof the rudder on that side upon which a positive pressure is acting. butthe flaps cooperating with the openings on the side where the negativepressure is acting are moved to cover the corresponding opening andthere-.

by close the opening to the passage of air through the same. Thiseffectively insures a positive pressure being present on the interior ofthe rudder at all times.

The ailerons 40 maybe subjected to an internal pressure in much the samemanner as the main section of the wing, except that in View of therelatively small size thereof the interior thereof maybe treated as asingle chamber or compartment or else may be divided transversely oftheir length into several compartments. In Fig. 4 the aileron 40 isshown as being provided with an opening adjacent the point of maximumexternal pressure thereon during flight so that such pressure may betransmitted to the interior of the same. This pressure may be'increasedby providing a scoop such as 66 for each opening 65 so that the airflowing against the same wi l maintain the internal pressure in excessof any external pressure acting on the aileron. While the provision ofsuch a scoop 66 will normally be unnecessary where an opening sure andinstead found necessary or desirable to place it at some intermediatepoint, such as.

the opening 67 in Figs. 5 and 6, the provision of a scoop such as 68 insuch a case is desirable in order that the pressure within the aileronmay lee-increased over that pressure acting on the surface adjacent theopening 67 to at least equal the maximum external pressure acting on thesection at any point. The construction disclosedin respect to theaileron 40 may. of course, be applied to a full wing section or partthereof. i

The same principles of internal pressure may he found desirable for usein connection with the fuselage. One mode of accomplishing this isillustrated in Fig. 1 in which the fuselage 69 is provided with a cabin70. In the particular construction shown, the interior of the fuselageis divided into two separate compartments 71 and 72, the compartment 71including the cabin 70. The interior of the compartment 71 may bemaintained under internal pressure by the provision of openings such as7 4 in the surface thereof for which CU-D rating scoops 75 mayor may notbe provided as desired. Ordinarily, however, in view of the fact thatthis compartment is adapted for the carrying of passengers. suchopenings 74 and scoops 75 may be undesirable in view of loss of pressurein the compartment which would result if one of the windows 76 wereopened during flight. The compartment 72, however, not being adapted forg the carrying of passengers, is preferably maintained under internalpressure. One mode of accomplishing this is shown in connection with thechamber 72, the particular means provided consisting of a duct 77connecting the interior of the chamber72 with the exterior surface ofthe plane at a point where a maximum air pressure is normally present.

Various types of so-called wing slots have been developed to prevent thepresence of air eddieson the upper surface of the wings at the time anairplane is in or about to go into a stall. These slots are usuallyemployed in connection with wing flaps or ailerons and may consist of anopening between the flap and the main wing so as to permit air to passfrom the lower to the upper surface of the wing in order to displace theeddies.

In the present invention I provide a novel form of wing slot that willresult in less disturbance in the passage of the wing through the" airthan in conventional constructions and that will be capable of supplyinga greater volume of air at the required point when necessary.

I also provide means wherein the construction may be utilized foreffecting a positive internal pressure in the wing, as previouslydescribed, as well as providing the wing slots.

Furthermore, I provide a means whereby the wing slots may beautomatically opened and closed in accordance with the necessity oftheir use.

Although the win generally indicated as 14 in Fig. 2 is provi ed onlywith an aileron 40v and no wing flaps, it will be readily apparent inthe following description and explanation that the aileron 40 may beextended to also serve as a wing flap or else that portion of the winginwardly of the aileron 40 may be formed to provide a wing flap at itstrailing edge, and in either case, the sections 3, 4 and 5 may beconsidered as being taken through either an aileron or a wing flap.

As indicated in Fig. 4, which shows a simple application of the .basicidea, an opening 41 is provided in the leading edge similar to theopening 24 illustrated in Fig. 2. The covering 19 rearwardly of themember 17 terminates adjacent the forward edge of the ailerons 40, whichmay pivot about the pins 43, and the rear edge of the lower portion ofthe covering 19 is bent upwardly into spaced but adjacent relationshipwith respectto the rear edge of the upper portion of the cover 19 so asto leave an opening 46 therebetwcen. The member 17 in line with theaileron 40, is apertured as at 42, and the main spar is apertured as at44. Extending between the edges of the opening 41 and the edges of theforward aperture 44 I prefer to provide a metal sheeting 45 formed topass the air through the same with a. minimum of disturbance andresistance.

During flight, air entering the opening 41 expands and passes throughthe length of the wing section and is discharged 'through the opening 46adjacent the line of connection between the main body portion of thewing 14 and aileron 40, and this discharge of air is sufficient toprevent the presence of undesirable eddies at or adjacent that point.The

- opening 46 provided between the rear edges of the covering 19 is ofmaterially lesser dimensions than the opening 41, so that more air iscapable of passing through the opening 41 and is capable of beingdischarged through the opening 46, with the result that a positivepressure is set up within the interior of the wing which serves the samepurpose as the interior pressure obtained in the construction describedin connection with Figs. 3, 7 and 8. This pressure and flow of air maybe in.- creased if deemed necessary or desirable by forming additionalopenings such as in the lower surface of the wing intermediate its edgesand providing such openings with cooperating scoops 81.. Where theaileron 40 is spaced from the rear edge of the wing, as indicated inFigs. 4, 5 and 6, a certain amount of air will also be permitted to passbetween the lower and upper surfaces of the wing at such point, as inconventional construction, and this may act to supplement the airescaping through the opening 46-from the interior of the wing. Theprovision of the slot 42 at the particular location shown is, of course,arbitrary, and it may be placed at any other point so as to dischargeair at any desired point on the up er surface of the wing, and obviouslymay e formed as a continuous opening or as a plurality of separateopenings.

Inasmuch as wing slots, as those described, are necessary as ageneralrule only at those times in which the angle of the wing approaches theangle of stall, the slots at any other time may be superfluous, and inFigs. 5 and. 6, I show means for closin the slots when they are notrequired. I othis by providing valvular means for the openings 41 and 46respectively. These valves may take the form illustrated in Figs. 5 and6 which is as follows: A simple flap valve 50 pivotally supported at 51is provided adjacent the opening 46 so as to be capable of being movedto close the same, as indicated in Fig. 6. The valve for the opening atthe leading edge may be formed in the following manner: The leading edgemay be formed with a semi-cylindrical end portion 52 and a valve memberbe provided having a complementary semi-cylindrical portion 53 overlyingthe portion 52 and pivotally supported on the same axial center as at 54by ribbed members such as 55. The valve member is pro vided with arearwardly extending portion 56 which closes the opening in the nosewhen the valve member is turned to bring the rear edge thereof intocontact with the covering 19 at the rear edge of the opening in thenose, as indicated in Fig. 6. An arm 57 pivotally supported at 58 andprojecting forwardly through the covering 19 is provided at its forwardedge with a small surface 59 of airfoil section. The lever 57 isprovided with an arm 60 extending downwardly therefrom which is freelyengaged between a pair of lugs 61 formed on one of the rib members 55, arod 62 pivotally connects the flap valve 50 with the arm 60. The edgesof the opening in the cover 19 through which the arm 57 projects areformed to provide two stops for limiting the upward and downwardmovement of the arm 57. The arm 57 and surface 59 are so arrangedrelative to the wing 14 that during normal angular travel of the wing14, the air forces acting on the surface 59 tends to move 'the surface59 downwardly with the arm 57 about the pivot point 58, or in acounter-clockwise direction as viewed in Figs. 5 and 6. This position ofthe arm 57 tends to move the arm 60 in the corresponding direction andacting through the lugs 61 tends'to move the valve inthe nose to theclosed position, indicated in Fig. 6, and at the same time actingthrough the rods 62, tends to move the flap valve 50 to closedposition,it being aided in this respect if desired by a coil spring 63.Should the angle of the wing be increased until it approaches its angleof stall, the air forces acting on the surface 59 will at that time bereversed, and acting on the bottom of the surface 59 will move itupwardly until stopped by the upper edge of the opening in the surface19 through which the arm 57 extends. of the arm 57 acting through thearm 60 will cause the valve portion 56 to move upwardly away from thecooperating portion of the covering 19 and uncover theopening in thenose of the wing, and moving the rod 62 forwardly will open the flapvalve 50, thus permitting air to enter the nose and escape through theopening 46 in order to displace the air eddies that tend to build upabove the wing at such times.

It is preferable that the connection between the arm 60 and the lug 61permit a small amount of lost motion so that during normal flight thepressure of the air on the leading edge acting on the portion 56 of theforward valve member will raise the portion 56 an amount sufficient topermit air to enter the interior of the wing so as to maintain thepositive pressure previously described. A slight coil spring such as 64maybe provided for limiting or controlling this action, if desired.

The forward valve members and the rear valve members may in practice beprovided either as a plurality of single separated members, orcontinuous members, as may be found most desirable, and manuallyoperated means may be provided, when desired, instead of theautomatically actuated means for controlling the valve members, andother formal changes may be made in the specific embodiment of theinvention described with out departing from the spirit or substance ofthe broad invention, the scope of which is commensurate with theappended claims.

I claim:

1.'In combination with a hollow airfoil having a single thickness stresstransmitting transmitting covering for said framework, and means forstiffening said cover by preventing the air pressure acting on theexterior of said covering from becoming substantially greater than theair pressure acting on the interior thereof comprising means forintroducing air to said interior from said exterior.

' 3. In an airplane, a structural part there- 2. In an airfoil, aframework, a stress This movement of comprising a framework and a smoothsheet metal covering therefor, said covering forming a major structuralstress transmitting element of said framework and being provided with anopening therein at or adjacent the point of maximum external airpressure acting thereon during flight, and means for maintaining theinterior surface of said covering under substantially the full airpressure transmitted thereto through said opening during flight wherebyto maintain the character of the stresses acting in said covering duringflight.

4. In an airplane, a hollow airfoil surface having openings on each sidethereof leading to the interior thereof, and means cooperating with saidopenings permitting air to enter said surface and'normally preventingits escape therefrom.

5. An airplane, a compartment therein, two or more air intake openingseach provided with check valves designed so that pressure is transmittedto the'interior only through those openings which are at or near a pointof maximum pressure acting on said compartment.

6. An airfoil of the stressed skin principle of design having an openingin the skin thereof for introducing airinto the interior of saidairfoil, said airfoil also provided with a second opening for conductingair from the interior of said airfoil to the exterior surface thereof ata point normally under a negative pressure, said openings being soproportioned as to normally maintain the interior of said airfoil undera positive pressure whereby to maintain said skin under tension toincrease the rigidity of said airfoil.

7. An airfoil having asheet metal skin forming a major stresstransmitting element of said airfoil, said airfoil having a passageconnecting the exterior surface of said skin with the interior surfacethereof, the relation of said passage to the pressure areas acting onthe exterior of said airfoil being a such as to create a pressuredifference on opposite surfaces of said skin whereby to maintain thecharacter and direction of the stresses acting on said skin.

8. An airfoil having a sheet metal skin forming a major stresstransmitting element of said airfoil, said airfoil having a passageconnecting theexterior surface of said skin with the interiorsurfacethereof, the rela tion of said passage to the pressure areasacting on the exterior of said airfoil being such as to create apressure difference on opposite surfaces of said skin whereby tonormally maintain said skin under tension during flight. j

9. An airfoil having a .sheet metal skin forming a major stresstransmitting element of saidairfoil, said airfoil having a passageconnecting the exterior surface of said connectin skin with the interiorsurface thereof, and a forwardly opening scoop cooperating with saidpassage exteriorly ,of said skin whereby to force air into said airfoiland create a pressure difference on opposite surfaces of said skin tonormally maintain said skin der tension during flight.

10. In an airfoil, a framework, a smooth sheet metal covering for saidframework secured thereto and forming a major stress resisting elementof said airfoil,said airfoill1aving an opening therein whereby the airpressure acting on the exterior surface of said covering adjacentsaid-opening is transmitted to the interior surface of said airfoiladjacent said opening, and means for maintaining said pressure on saidinterior surface during flight whereby to maintain the direction andcharacter of stresses in said covering.

11. In an airplane wing, in combination, a framework and a substantiallysmooth sheet metal skin enclosing said framework and serving as a majorstructural stress transmitting element of said wing, said coveringhaving an opening therein substantially at the point of maximum airpressure acting on said Wing during flight and being otherwisesubstantially closed, whereby the interior surface of said skin' isconstantly subjected during flight to a pressure at least as great asthe pressure simultaneously acting upon the exterior surface thereof tomaintain the character of the stresses, acting on said skin.

12. In an airplane,-a substantially closed compartment formed thereinhaving a sheet metal covering forming an exterior surface of saidairplane andserving as a major stress transmitting element thereof, saidcovering having a passageway therethrough connectingthe interior surfaceof said covering with 21-point exterior thereto at which the pressure 0the air in flight is at least as great as the maximum pressuresimultaneously acting on said covering, whereby said covering is comisitanjtly maintained under tension during 13. Inan airplane, aplurality of substantially closed compartments formed therein eachhaving a covering forming an exterior surface of said airplane, saidcoverings forming a majorvstress transmitting element of said airplaneand each being provided with an opemn 1 therethrough connecting theinterior sur ace of each of said coverings with exterior surface thereofat that point there on at which the maximum air pressurev during flightis resent, whereby tomaintain the interior sur ace of each of saidcoverings under a,.po sitive outwardly acting pressure to maintain thetension therein.

14. An airfoil having a sheet metal skin forming a major stresstransmitting element of said airfoil, said airfoil having a passage theexterior surface of said skin with the interior surface thereof, therelation of said passage to the pressure areas acting on the exterior ofsaid airfoil being such as to create a pressure difference on oppositesurfaces of said skin when said passage is open whereby to normallymaintain said skin under tension during flight, and a valve for closingsaid passage. I

15. An airfoil having a sheet metal skin forming a major stresstransmitting element of said airfoil, said airfoil having a passageconnecting the exterior surface of said skin with the interior surfacethereof, the relation of said passage to the pressure areas acting onthe exterior of said airfoil being such as to create a pressuredifference on opposite surfaces of said skin when said passage is openwhereby to normally maintain said skin under tension during flight, avalve for closing said passage, and means controlled by the angle ofattack of said airfoil for controlling said valve.

RALPH H. UPSON.

